It is hard to believe that the lands we see today, so far from the sea, were submerged in water in the distant past. One of the most concluding evidences is the appearance of fossils from marine animals in continental materials. This is the case of the deposit in Bueña.
The megaplanolites are located in a stratum of limestone deposited during the Jurasic Era (Mesozoic period), that form a succession with other rocks (loams, sandstones and other limestones). It is about fossilized footprints of great size, left by a giant crustacean that would move creeping over a seabed of shallower and warm waters. Its diameter is about 20 centimetres and its maximum lenght is 10 metres. The difference between the size of this specie and the other from the Planolites genus have made the creation of a new genus called Megaplanolite. The stratum in which the icnitas (tracks) were formed, were folded at the Cretaceous (Mesozoic period) until acquire its current vertical layout. The subsequent erosion unearthed them and left revealed.
By the quality of the remains found it is considered unique among the European Sites of this type and of a great importance in the Spanish Geological Patrimony, described as Geological Point of Interest.
The special characteristics of conservation and fossilization, as much as its dimensions allow the excellent preservation of the remains. Thus has a great educational and cultural attractive, and for this reason has an interpretation point of the landscape, created thanks to the works from Calvo (Regional Geology) between 1984 and 1992. It is because of that, why is considered as Geological Heritage in Aragon.